/*
 *       Copyright (c) 2008-2009 All rights reserved
 *               Asemantics S.r.l
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by
 *        Asemantics S.r.l."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by Asemantics S.r.l.
 *    the Semantic Web company, Rome, London, Leiden and its contributors.
 *
 * 5. Neither the name of the company nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */


package com.asemantics.poco.persistence;

import java.util.Properties;
import java.io.IOException;
import java.io.InputStream;

/**
 * Defines the configuration of the {@link PersitorDefaultImpl} class.
 *
 * @author Michele Mostarda ( michele.mostarda@gmail.com )
 */
public class Configuration {

    public static final String PERSISTENCE_MANAGER_FC = "javax.jdo.PersistenceManagerFactoryClass";
    public static final String DRIVER_NAME = "javax.jdo.option.ConnectionDriverName";
    public static final String CONNECTION_URL = "javax.jdo.option.ConnectionURL";
    public static final String USERNAME = "javax.jdo.option.ConnectionUserName";
    public static final String PASSWORD = "javax.jdo.option.ConnectionPassword";

    /**
     * List of expected properties.
     */
    private static final String[] EXPECTED_PROPERTIES = {
        PERSISTENCE_MANAGER_FC,
            DRIVER_NAME,
            CONNECTION_URL,
            USERNAME,
            PASSWORD
    };

    /**
     * Internal properties.
     */
    private Properties properties;

    /**
     * Configuration constructor.
     *
     * @param p properties.
     */
    private Configuration(Properties p) {
        properties = p;
    }

    /**
     * Creates a configuration object.
     *
     * @param pathToProps path of properties file in classpath.
     * @param validate flag to activate properties validation.
     * @return a new configuration instance.
     * @throws ConfigurationException if an error occurs during while loading or validating porperties.
     */
    public static Configuration createConfiguration(String pathToProps, boolean validate) 
    throws ConfigurationException {
        InputStream is = Configuration.class.getResourceAsStream(pathToProps);
        if(is == null) {
            throw new ConfigurationException("Cannot find resource '" + pathToProps + "' in classpath.");
        }
        Properties properties = new Properties();
        try {
            properties.load(is);
        } catch (IOException ioe) {
            throw new ConfigurationException("Error while loading resources from file: '" + pathToProps + "'.", ioe);

        }

        if( validate) {
            validate(properties);
        }
        
        return new Configuration(properties);
    }

    /**
     * Creates a configuration object.
     *
     * @param pathToProps path of properties file in classpath.
     * @return a new configuration instance.
     * @throws ConfigurationException if an error occurs during while loading or validating porperties.
     */
    public static Configuration createConfiguration(String pathToProps)
    throws ConfigurationException {
        return createConfiguration(pathToProps, true);
    }

    /**
     * Validates the properties.
     * 
     * @param properties
     * @throws ConfigurationException
     */
    protected static void validate(Properties properties) throws ConfigurationException {
        for (String property : EXPECTED_PROPERTIES) {
            if (!properties.containsKey(property)) {
                throw new ConfigurationException("Expected property '" + property + "'.");
            }
        }
    }

    protected Properties getProperties() {
        return properties;
    }

}